Lubricating oil composition



Patented Aug. 19, 1941 L UBR ICATIN G OIL COMPOSITION Franklin M. Watkins, Chicago, Ill., assignor to Sinclair Refining Company, New York, N.

corporation of Maine No Drawing. Application March 27, 1940,

Serial No. 326,191

Claims.

My invention relates to improvements in compounded petroleum lubricating oils. ticularly, my invention relates to improvements in lubricating oil compositions of the type described in Letters Patent No. 2,081,075, granted May 18, 1937, on an application of .firnold C. Vobach. The improved lubricants of my invention have better properties with respect to corrosion and equally'satisfactory properties with respect to anti-sludging and anti-ring sticking characteristics.

The improved lubricating'oil compositions of my invention consist essentially of a petroleum lubricating oil, basic calcium phenyl'stearate, a solubilizer for the basic calcium phenyl stearate and a thioamid. In referring to "petroleum lubricating oil, I refer to lubricating oils of petroleum origin having viscosities upwards of 50-70 seconds at 100 F. Saybolt Universal. In referring to basic calcium phenyl stearate, I refer to calcium soaps of phenyl stearic acid containing a proportion of calcium, .as hydroxide, greater than More par- 'than a .very minor part of any normal service period. Basic calcium phenyl stearate, moreoveryis not freely soluble in petroleum lubricating oil but tends to gel and to alter the normally liquid character of the oil, even in very small proportions, The thioamids are anti-oxidants,

. but in the presence of free phenyl stearic acid they seem to be ineffective, perhaps because of pro-oxidant activity of phenyl stearic acid. Thus, neither the basic calcium phenyl stearate nor the thioamids, used alone, are effective to accomplish the purposes of my invention.

According to my invention, basic calcium phenyl stearate and a thioamid are used together to effect a substantial improvement in the properties of the lubricating oil composition with respect to corrosion and basic calcium phenyl stearate and a solubilizer are used tothat corresponding to the neutral soap. The

basic soap may be prepared, for example, by preparing the phenyl stearic acid or a fraction containing phenyl stearic acid as described in said Letters Patent, and neutralizing this material with an excessof lime. The usual solubilizing agents for soaps in petroleum oils are generally useful as fsolubilizers, oil soluble polar compounds being particularly advantageous. The aliphatic, the aromatic and the mixed aliphaticaromatic 'thloami'dsare useful in these lubricating oil compositions. Illustrating useful proportions, the lubricating oil compositions of my invention may comprise 05-25% basic calcium phenyl stearate, 0.5-3.0% solubilizer and 0.5-1 .0% thioamid (percentages by weight on the composition).

Free fatty acids, such as phenyl stearic acid,

have corrosive tendencies with respect to some bearing metals, particularly copper-lead alloys, under conditions, particularly elevated temperatures, encountered in the operation of internal combustion engines. Oxidation of petroleum lubricating oil, incident to engine operation, tends to form organic acids which may themselves be corrosive or which may liberate free fatty acids from any soaps present. The use of a basic soap, such as basic calcium phenyl stearate, retards, for a short interval, the liberation of free fatty acids, but the amount of free base available to neutralize free acid that can thus be incorporated into the lubricating oil composition is. as

a maximum; too small to be eifective over more acid.

gether to maintain the anti-sludging and antiring sticking properties characteristic of calcium phenyl stearate. The thioamid apparently acts to maintain a condition, with respect to free organic acids, established by the basic calcium phenyl stearate while the solubilizer apparently enables the basic soap to function as though it were the neutral calcium soap of phenyl stearic Calcium phenyl stearate can be represented by the empirical formula RCOOCaOOCR Basic calcium phenyl stearate can be represented by the empirical formula RCOOCaOH In referring to basic calcium; phenyl stearate as a component of the lubricating oil composition, I refer to basic calcium phenyl stearate as such and to mixtures, or compounds of association, containing basic calcium phenyl stearate and calcium phenyl stearate. For example, in a lubricating oil composition embodying my invention containing 1.26% of phenyl stearic acid. as basic calcium phenyl stearate or a mixture of basic calcium phenyl stearate and calcium phenyl stearate, the calcium content may range from about 0.14% down to something more than about 0.07%, and I have found a mixed soap affording a calcium content of 0.08%-0.09% in such a composition to be particularly advantageous. The amount of basic calcium phenyl stearate used in the lubricating oil composition of my invention is insufficient, in conjunction with the character of the petroleum lubricating oil itself.

The basic calcium phenyl stearate is with advantage incorporated into the oil by compounding the oil and the phenyl stearic acid and thereafter neutralizing the acid with anexcess of lime in the oil to. form the basic soap, usually a mixture of the basic and the neutral soap.

Solubilizers useful in the lubricating oil compositions of'my invention include for example lauryl alcohol, lauryl mercaptan, methyl-phenyl stearate, di-amyl phenol and deglycerinated 1W- drogenated sperm oil. Mixtures of such solubilizers, for example of lauryl alcohol and lauryl mercaptan or of lauryl alcohol and di-amyl phenol, are also useful. Of these solubilize rs and of such mixtures, proportions approximating are generally useful. The proportion of any specific solubilizer used will accord with its particular properties. The phenyl stearate compound seems to have some efiect as a solubilizer wlthrespect to the thioamids, par- I ticularly at lower temperatures, and it may be that the thioamids have some such but limited eiiect with respect to basic calcium phenyl stearate.

Thioamids useful in the lubricating oil c'om'positions of my invention include for example t'hiobenzanilid, N-lauryl-thio-benzamid, N-butylthio-stearamid andphenyl-thio-stearamid. The first of these three represents the aromatic thioamids, the second and fourth the mixed aliphatic-aromatic thioamids, and the third the aliphatic thioamids. This class of compounds may be represented by the empirical formula phiding of bearing metals in the particular service intended.

The improved lubricating oil compositions of my invention will be further illustrated by the following specific examples. Each of these compositions was compounded of a South Texas pale 'oil having a viscosity of about 500 seconds F. Saybolt Universal and boiling 10% up to 700 F. and 90% up to 900 F., approximately. Composition A, included for comparison, contained about 1 /3% calcium phenyl stearate but no solubilizer or thioamid. Compositions B, C, .D

and E, embodying my invention, contained about 1 basic calcium phenyl stearate (0.088% calcium) and, respectively, 0.5% thiobenzanilid and 1% lauryl alcohol, 1.0% N-lauryl-thio-benzamid and 0.25% lauryl alcohol and 1.0% diamyl lauryl alcohol, and 0.5% phenyl-thio-stearamid and 1% lauryl alcohol.

A B G D E Gravity API l9. 8 20.1 20. 0 l9. 2 20. 3 Flash F 385 365 375 375 375 Fire "If 435 420 435- 430 415 Viscosity at 100 F. Saybolt Universal 578 499 528 486 516 Viscosity at 2l0 F. Saybolt Universal 58. 6 55. 5 63. 9 56. 4 55. 7 Carbon rcsiduc 0. 067 0.107 0. 076 0. 082 0. 121 Ash 128 119 173 181 077 Acid number 075 08 01 Basic 06 Saponiiicatlon number. l. 71 l. 1. 42' 1. 6 1. 8

The Indiana Oxidation Test is AIE. Journal, 1

34, 172-3, 1934) of each of the four compositions B, C, D and E ranged vfrom 25 to more than 30 hours, composition E being the best at 38 hours followed by compositions B and D at 30.5 hours. All four compositions, B, C, D and E, in service in a Diesel type engine, left the engine substantially free from sludge and carbon" deposits and adequately lubricated the moving parts of the engine. l

While the lubricating oil compositions of the foregoing examples embody specifically a South Cir phenol, 1.0% N-butyl-thio-stearamid and 1%,

. of a solubilizer and about -0.5'1.0%

Texas lubricating oil, my invention is generally useful in lubricating oil compositions embodying petroleum lubricating oil from 'paraflin base erudes, asphaltic base crudes and mixed base crudes.

It appears matic stearic acids, generally, are useful for the purposes of my invention. Other aromatic stearic acids, tolyl stearic acid, xylyl stearic acid, naphanthracyl stearic acid for example, may be made by methods generally similar to the method for the production of phenyl stearic acid and may be saponified with an excess of lime, in a similar manner, to produce the corresponding basic calcium soaps.

I claim: 1. A liquid lubricating oil composition comprising a petroleum lubricating oil, about 0.5-2.5% of basic calcium phenyl of a solubilizer and about 0.5-1.0% of a thioamid.

2. A liquid lubricating'oil composition comprising a petroleum lubricating oil, about 0.5-2.5% of basic calcium phenyl of a solubilizer and about 0.5-1.0%

thioamid.

3. A liquid lubricating oil composition comprising a petroleum lubricating oil, about 05-25% of basic calcium phenyl stearate, about 0.53.0%

of an alithyl stearic acid and of an'aromatic phatic thioamid.

4. A liquid lubricating oil composition comprising a petroleun lubricating oil, about 0.5-2.5% of basic calcium phenyl stearate, about 0.5-3.0% of a solubilizer and about.0.5-1.0% of a mixed aromatic-aliphatic thioamid.

5. A liquid lubricating oil composition comprising a petroleum lubricating oil, about 05-25% of a basic calcium soap of an aromatic stearic acid, about 0.5-3'.0%' of a solubilizer and about 05-10% of a thioamid.

FRANKLIN M. WATKINS.

that the basic calcium soaps of aro-.

stearate, about 0.5-3.0%

stearate, about 0.5-3.0% 

